Novolak type phenolic resins and methods of manufacturing thereof

ABSTRACT

One of the objects of the present invention is to offer novolak type phenolic resins which use phenols and aldehydes as raw materials and give narrow molecular weight distributions. 
     The novolak type phenolic resins of the present invention are those obtained by condensation reaction of phenols with aldehydes in the presence of an oxycarboxylic acid having carboxyl groups, --COOH, and alcoholic hydroxyl groups, --OH, in one molecule. Thus obtained novolak type phenolic resins show narrow molecular weight distributions, lower viscosity in molten state and, as a consequence, uniformity in curing time.

This is a divisional application of Ser. No. 08/571,736 filed Dec. 13,1995, now pending.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to novolak type phenolic resins offering narrowmolecular weight distributions, and methods of manufacturing thereof.

2. Prior Art

Conventionally, novolak type phenolic resins are obtained by makingphenols react with aldehydes in the presence of an acidic catalyst, andare used in a wide variety of fields. However, with such conventionalnovolak type phenolic resins, the molecular weight distributions arewide, which results in such drawbacks as non-uniformity in resin curingtime, and high viscosity in molten state.

To eliminate these problems, various methods have conventionally beenused. For example, by making phenols react with aldehydes in thepresence of an acidic catalyst in an organic solvent system which iscomposed of a good solvent and a poor one, a novolak resin offering anarrow molecular weight distribution has been obtained. A method ofmanufacturing novolak type phenolic resins by making phenols react withaldehydes in the presence of an acidic catalyst, and then treating thereaction product with a thin film evaporator has been proposed. Asdisclosed in Patent KOKAI (Laid-Open) No. 1-105243 and Patent KOKAI(Laid-Open) No. 6-41262, a method with which phenols are made to reactwith aldehydes in the presence of an acidic catalyst, and then thereaction product is washed with water or a mixed solvent of water and agood solvent for fractionation has been proposed.

However, with these methods of manufacturing, the processes arecomplicated, the yields of resin have been small, and the molecularweight distributions have not always been sufficiently narrow.

SUMMARY OF THE INVENTION

The present invention has been developed in consideration of the abovesituation, and it intends to offer novolak type phenolic resins havingnarrow molecular weight distributions which are manufactured fromphenols and aldehydes, and to offer methods of manufacturing that allowthese novolak type phenolic resins to be obtained at high yields.

The novolak type phenolic resins of the present invention are thoseobtained by condensation reaction of phenols with aldehydes in thepresence of an oxycarboxylic acid having carboxyl groups, --COOH, andalcoholic hydroxyl groups, --OH, in one molecule. Thus, obtained novolaktype phenolic resins show narrow molecular weight distributions, lowerviscosity in molten state and, as a consequence, uniformity in curingtime.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the infrared absorption spectrum revealing the absorptioncondition due to the carboxylic acid at 1740 cm⁻¹ before washing withthe preferred embodiment 1.

FIG. 2 shows the infrared absorption spectrum revealing the absorptioncondition due to the carboxylic acid at 1740 cm⁻¹ after washing with thepreferred embodiment 1.

FIG. 3 shows the result of determination by gel permeationchromatography for the resin provided by the preferred embodiment 1.

FIG. 4 shows the result of determination by gel permeationchromatography for the resin provided by the preferred embodiment 2.

FIG. 5 shows the result of determination by gel permeationchromatography for the resin provided by the preferred embodiment 3.

FIG. 6 shows the result of determination by gel permeationchromatography for the resin provided by the preferred embodiment 4.

FIG. 7 shows the result of determination by gel permeationchromatography for the resin provided by the preferred embodiment 5.

FIG. 8 shows the result of determination by gel permeationchromatography for the resin provided by the preferred embodiment 6.

FIG. 9 shows the result of determination by gel permeationchromatography for the resin provided by the preferred embodiment 7.

FIG. 10 shows the result of determination by gel permeationchromatography for the resin provided by the preferred embodiment 8.

FIG. 11 shows the result of determination by gel permeationchromatography for the resin provided by the preferred embodiment 9.

FIG. 12 shows the result of determination by gel permeationchromatography for the resin provided by the preferred embodiment 10.

FIG. 13 shows the result of determination by gel permeationchromatography for the resin provided by the comparison example 1.

DETAILED DESCRIPTION OF THE INVENTION

The novolak type phenolic resins of the invention are those obtained bycondensation reaction of phenols with aldehydes in the presence of anoxycarboxylic acid having carboxyl groups, --COOH, and alcoholichydroxyl groups, --OH, in one molecule.

The novolak type phenolic resins preferably have a ratio of (a)/(b)which is 0.05 or higher, where (a) is the number of units, with acarboxyl group, --COOH, and an alcoholic hydroxyl group, --OH, in thesaid oxycarboxylic acid being considered to form one unit, multiplied bythe number of moles of the oxycarboxylic acid, and (b) is the number ofaldehyde groups contained in one molecule of the aldehydes multiplied bythe number of moles of the aldehydes.

The novolak type phenolic resins are preferably those in which the saidoxycarboxylic acid is any one of tartaric acid, citric acid, and malicacid or a mixture of any two or all of these.

The phenols are preferably any one of phenol, cresol, xylenol, bisphenolA, bisphenol F, pyrocatechol, resorcinol, and pyrogallol or a mixture ofany two or more of these.

The aldehydes are preferably any one of formaldehyde, paraformaldehyde,trioxane, tetraoxane, benzaldehyde, salicylaldehyde,p-hydroxybenzaldehyde, and terephthalaldehyde or a mixture of any two ormore of these.

The ratio of (a)/(b) is preferably 0.1 to 1.0, where (a) is the numberof aldehyde groups contained in one molecule of the said aldehydesmultiplied by the number of moles of the aldehydes, and (b) is thenumber of aromatic rings having a hydroxyl group contained in onemolecule of the said phenols multiplied by the number of moles of thephenols.

The novolak type phenolic resins can be obtained by using as catalyststhe said oxycarboxylic acid in conjunction with any one of hydrochloricacid, sulfuric acid, oxalic acid, and p-toluenesulfonic acid, which areused as an acid catalyst in manufacturing of conventional novolak typephenolic resins.

The method of manufacturing the novolak type phenolic resin is one inwhich phenols react with aldehydes in the presence of an oxycarboxylicacid catalyst having carboxyl groups, --COOH, and alcoholic hydroxylgroups, --OH, in one molecule.

The novolak type phenolic resin can be obtained by making anoxycarboxylic acid having carboxyl groups, --COOH, and alcoholichydroxyl groups, --OH, in one molecule react with aldehydes, and thenmaking the reaction product react with phenols.

The novolak type phenolic resin can also be obtained by making phenolsreact with aldehydes in the presence of an oxycarboxylic acid catalysthaving carboxyl groups, --COOH, and alcoholic hydroxyl groups, --OH, inone molecule; after completion of the reaction, washing the reactionmixture with water to remove the catalysts; and then dehydrating andconcentrating the resulted mixture.

The novolak type phenolic resin can also be obtained by making anoxycarboxylic acid having carboxyl groups, --COOH, and alcoholichydroxyl groups, --OH, in one molecule react with aldehydes, then makingthe reaction product react with phenols, and after completion of thereaction, washing the reaction mixture with water to remove thecatalysts and then dehydrating and concentrating the resulted mixture.

Here is a detailed description of the present invention.

Before completion of the present invention, the inventors of the presentinvention eagerly and repetitively studied about how to solve the saidproblems, and found that, by using an oxycarboxylic acid having carboxylgroups, --COOH, and alcoholic hydroxyl groups, --OH, in one molecule,such as any one of tartaric acid, citric acid, and malic acid or amixture of any two or all of these, as a catalyst for making phenolsreact with aldehydes, the aldehydes react with the oxycarboxylic acidbefore they react with the phenols, which results in a novolak typephenolic resin with a narrow molecular weight distribution obtained at ahigh yield.

With the present invention, the condensation reaction of phenols withaldehydes may be performed by the single-stage process that charges thewhole stock including the said oxycarboxylic acid at a time, however, byusing the two-stage process, which first makes the oxycarboxylic acidreact with the aldehydes, and then charges the phenols for reaction, anovolak type phenolic resin with a still narrower molecular weightdistribution can be obtained.

With either of the reaction processes, by washing the reaction mixturewith water to remove the catalysts after completion of the reaction, andthen dehydrating and concentrating the resulted mixture, a novolak typephenolic resin with a narrower molecular weight distribution can beobtained at a high yield.

Here is a detailed description of the preferred embodiment of thepresent invention.

The novolak type phenolic resin with the preferred embodiment of thepresent invention is that obtained by making phenols react withaldehydes with the use of an oxycarboxylic acid having carboxyl groups,--COOH, and alcoholic hydroxyl groups, --OH, in one molecule as acatalyst.

As the said phenols, any one of phenol, cresol, xylenol, bisphenol A,bisphenol F, pyrocatechol, resorcinol, and pyrogallol or a mixture ofany two or more of these is used.

As the said aldehydes, any one of formaldehyde, paraformaldehyde,trioxane, tetraoxane, benzaldehyde, salicylaldehyde,p-hydroxybenzaldehyde, and terephthalaldehyde or a mixture of any two ormore of these is used.

As the oxycarboxylic acid catalyst, any one of tartaric acid, citricacid, and malic acid or a mixture of any two or all of these is used,and in conjunction with it, any one of hydrochloric acid, sulfuric acid,oxalic acid, and p-toluenesulfonic acid, which are used as a catalystfor manufacturing of conventional novolak type phenolic resins, can beused.

The reaction mole ratio of the said phenols to the said aldehydes, i.e.,(a)/(b), where (a) is the number of aldehyde groups contained in onemolecule of the aldehydes multiplied by the number of moles of thealdehydes, and (b) is the number of aromatic rings having a hydroxylgroup contained in one molecule of the phenols multiplied by the numberof moles of the phenols, is generally 0.1 to 1.0, preferably, 0.5 to0.9. If the ratio of (a)/(b) is lower than 0.1, the concentration offree phenols in the resulted novolak type phenolic resin becomes large,while the (a)/(b) ratio higher than 1.0 will give too wide molecularweight distribution to the resulted resin.

With the said oxycarboxylic acid as a catalyst, the ratio of (a)/(b) isgenerally 0.05 or higher, preferably 0.25 or higher, where (a) is thenumber of units, with a carboxyl group, --COOH, and an alcoholichydroxyl group, --OH, in the oxycarboxylic acid being considered to formone unit, multiplied by the number of moles of the oxycarboxylic acid,and (b) is the number of aldehyde groups contained in one molecule ofthe aldehydes multiplied by the number of moles of the aldehydes. If theratio of (a)/(b) is lower than 0.05, the molecular weight distributionwill be brought to near that which would be given if an acid that isused as a catalyst for manufacturing of a conventional novolak typephenolic resin were used. The higher the ratio of (a)/(b), the narrowerthe molecular weight distribution for the novolak type phenolic resinobtained will be.

With the preferred embodiment of the present invention, the condensationreaction of phenols with aldehydes may be performed by the single-stageprocess that charges the whole stock including the said oxycarboxylicacids at a time, however, by using the two-stage process, which firstmakes the oxycarboxylic acid react with the aldehydes, and then chargesthe phenols for reaction, the molecular weight distribution will bestill narrower.

After completion of the reaction, the reaction mixture is washed withwater to remove the catalysts. Then by dehydrating and concentrating theresulted mixture, a novolak type phenolic resin with a narrowermolecular weight distribution is obtained.

Here is a detailed description of the particular preferred embodimentsof the present invention, however, the present invention is not limitedto these preferred embodiments.

Preferred Embodiment 1

141 g of phenol, 41.9 g of 86% paraformaldehyde, and 180 g of tartaricacid were placed in a 500-ml four-necked separable flask equipped with athermometer, a stirrer, and a reflux condenser, and heated to 120° C.,and the reaction was continued under reflux for 4 hours. Aftercompletion of the reaction, 141 g of pure water was added, and afterstirring for 30 min., the aqueous layer being separated from the resinwas removed.

The washing process, i.e., the procedure between water adding andaqueous layer removal was repeated until most of the catalyst wasremoved. The catalyst removal was identified by using the absorption dueto the carboxylic acid at 1740 cm⁻¹, as shown in FIGS. 1 and 2, as theindex. FIG. 1 shows the infrared absorption spectrum revealing theabsorption condition due to the carboxylic acid at 1740 cm⁻¹ beforewashing with the preferred embodiment 1, while FIG. 2 shows the infraredabsorption spectrum revealing the absorption condition due to thecarboxylic acid at 1740 cm⁻¹ after washing with the preferred embodiment1.

After washing, the resulted mixture was dehydrated and concentrated toobtain 151 g of a light-yellow, clear novolak type phenolic resin. FIG.3 shows the result of determination by gel permeation chromatography forthe resin provided by the preferred embodiment 1.

FIG. 1, which shows the infrared absorption spectrum revealing theabsorption condition due to the carboxylic acid at 1740 cm⁻¹ beforewashing, permits the presence of the tartaric acid to be identified.Also, FIG. 2, which shows the infrared absorption spectrum revealing theabsorption condition due to the carboxylic acid at 1740 cm⁻¹ afterwashing, permits the removal of the tartaric acid to be identified.

Preferred Embodiment 2

By tracing the same precedures as those in the above preferredembodiment 1 except that the 180 g of tartaric acid used in thepreferred embodiment 1 was changed to 45 g, 147 g of a light-yellow,clear novolak type phenolic resin was obtained. FIG. 4 shows the resultof determination by gel permeation chromatography for the resin providedby the preferred embodiment 2.

Preferred Embodiment 3

41.9 g of 86% paraformaldehyde, and 180 g of tartaric acid were placedin the same apparatus as that used in the above preferred embodiment 1,and heated to 120° C., and the reaction was continued under reflux for 2hours.

After completion of the reaction, the contents were cooled to below 40°C., 141 g of phenol was added and heated to 120° C., and the reactionwas continued under reflux for 4 hours. After completion of thereaction, 141 g of pure water was added, and after stirring for 30 min.,the aqueous layer being separated from the resin was removed. Thewashing process, i.e., the procedures between water adding and aqueouslayer removal were repeated until most of the catalyst was removed.After washing, the resuted mixtue was dehydrated and concentrated toobtain 152 g of a light-yellow, clear novolak type phenolic resin. FIG.5 shows the result of determination by gel permeation chromatography forthe resin provided by the preferred embodiment 3.

Preferred Embodiment 4

By tracing the same procedures as those in the above preferredembodiment 3 except that the 180 g of tartaric acid used in the abovepreferred embodiment 3 was changed to 1800 g, the internal volume of thereaction vessel was changed to 3000 ml, and the quantity of water forthe first washing was changed to 1000 g, 154 g of a light-yellow, clearnovolak type phenolic resin was obtained. FIG. 6 shows the result ofdetermination by gel permeation chromatography for the resin provided bythe preferred embodiment 4.

Preferred Embodiment 5

By tracing the same procedures as those in the above preferredembodiment 3 except that the 41.9 g of 86% paraformaldehyde used in thepreferred embodiment 3 was changed to 36 g of trioxane, 152 g of alight-yellow, clear novolak type phenolic resin was obtained. FIG. 7shows the result of determination by gel permeation chromatography forthe resin provided by the preferred embodiment 5.

Preferred Embodiment 6

By tracing the same procedures as those in the above preferredembodiment 3 except that the 41.9 g of 86% paraformaldehyde used in thepreferred embodiment 3 was changed to 97.3 g of 37% formalin, 147 g of alight-yellow, clear novolak type phenolic resin was obtained. FIG. 8shows the result of determination by gel permeation chromatography forthe resin provided by the preferred embodiment 6.

Preferred Embodiment 7

41.9 g of 86% paraformaldehyde, and 230.4 g of citric acid were placedin the same apparatus as that used in the above preferred embodiment 1,and heated to 120° C., and the reaction was continued under reflux for 2hours. After completion of the reaction, the contents were cooled tobelow 40° C. and taken out, and 272.3 g of a solid reaction product wasobtained.

Then, 141 g of phenol was placed in the same apparatus as that used inthe above preferred embodiment 1, heated to 60° C., and kept at 60° C.,while 272.3 g of the solid reaction product from the paraformaldehydeand citric acid was gradually added to be dissolved. After completion ofthe dissolution, the contents were heated to 120° C., and the reactionwas continued under reflux for 4 hours. After completion of thereaction, 141 g of pure water was added, and after stirring for 30 min.,the aqueous layer being separated from the resin was removed. Thewashing process, i.e., the procedures between water adding and aqueouslayer removal were repeated until most of the catalyst was removed.

After completion of the washing, the resulted mixture was dehydrated andconcentrated to obtain 141 g of a light-yellow, clear novolak typephenolic resin. FIG. 9 shows the result of determination by gelpermeation chromatography for the resin provided by the preferredembodiment 7.

Preferred Embodiment 8

By tracing the same procedures as those in the above preferredembodiment 3 except that the 180 g of tartaric acid used in thepreferred embodiment 3 was changed to 161 g of malic acid, 147 g of alight-yellow, clear novolak type phenolic resin was obtained. FIG. 10shows the result of determination by gel permeation chromatography forthe resin provided by the preferred embodiment 8.

Preferred Embodiment 9

By tracing the same procedures as those in the above preferredembodiment 3 except that the 180 g of tartaric acid used in thepreferred embodiment 3 was changed to 180 g of tartaric acid used inconjunction with 1.41 g of oxalic acid, 152 g of a light-yellow, clearnovolak type phenolic resin was obtained. FIG. 11 shows the result ofdetermination by gel permeation chromatography for the resin provided bythe preferred embodiment 9.

Preferred Embodiment 10

By tracing the same procedures as those in the above preferredembodiment 3 except that the 141 g of phenol used in the preferredembodiment 3 was changed to 162 g of orthocresol, and the quantity ofwater used for the washing process was changed to 162 g, 176 g of alight-yellow, clear novolak type phenolic resin was obtained. FIG. 12shows the result of determination by gel permeation chromatography forthe resin provided by the preferred embodiment 10.

Comparison Example 1

141 g of phenol, 97.3 g of 37% formalin, and 0.99 g of oxalic acid wereplaced in the same apparatus as that used in the above preferredembodiment 1, and heated to 100° C., and the reaction was continuedunder reflux for 4 hours. After completion of the reaction, the reactionmixture was dehydrated and concentrated to obtain 138 g of alight-yellow, clear novolak type phenolic resin. FIG. 13 shows theresult of determination by gel permeation chromatography for the resinprovided by the comparison example 1.

Table 1 gives the results of determination of the softening point andmolecular weight distribution, and the yield for each of the resinsprovided by the above preferred embodiments 1 to 10, and the comparisonexample 1.

The said molecular weight distribution was determined by gel permeationchromatography, and as a measure of the breadth of the molecular weightdistribution, the ratio of weight-average molecular weight (Mw) tonumber-average molecular weight (Mn) by polystyrene conversion was used.

                                      TABLE 1    __________________________________________________________________________            Preferred                 Preferred                      Preferred                           Preferred                                Preferred                                     Preferred                                          Preferred                                               Preferred                                                    Preferred                                                         Preferred                                                              Compar-            embodi-                 embodi-                      embodi-                           embodi-                                embodi-                                     embodi-                                          embodi-                                               embodi-                                                    embodi-                                                         embodi-                                                              ison            ment ment ment ment ment ment ment ment ment ment example            1    2    3    4    5    6    7    8    9    10   1    __________________________________________________________________________    Phenols Phenol                 Phenol                      Phenol                           Phenol                                Phenol                                     Phenol                                          Phenol                                               Phenol                                                    Phenol                                                         o-cresol                                                              Phenol    Aldehydes            86%  86%  86%  86%  Trioxane                                     37%  86%  86%  86%  86%  37%            (F) n                 (F) n                      (F) n                           (F) n     formalin                                          (F) n                                               (F) n                                                    (F) n                                                         (F)                                                              formalin    (a)/(b) ratio            0.8  0.8  0.8  0.8  0.8  0.8  0.8  0.8  0.8  0.8  0.8    Catalyst species            Tartaric                 Tartaric                      Tartaric                           Tartaric                                Tartaric                                     Tartaric                                          Citric                                               Malic                                                    Tartaric                                                         Tartaric                                                              Oxalic            acid acid acid acid acid acid acid acid acid and                                                         acid acid                                                    oxalic acid    (a)/(b) ratio            2    0.5  2    20   2    2    1    1    2    2    --    Softening            97   91   90   103  95   95   107  114  95   89   112    point (°C.)    M.sub.W /M.sub.N            1.29 1.68 1.24 1.07 1.18 1.40 1.31 1.88 1.17 1.05 5.51    Yield   107  104  108  109  108  104  100  103  108  109  98    (wt-%/phenols)    Number of            4    4    4    5    4    4    4    4    4    4    0    washing times    Reaction            Single-                 Single-                      Two- Two- Two- Two- Two- Two- Two- Two- Conven-    formulation            stage                 stage                      stage                           stage                                stage                                     stage                                          stage                                               stage                                                    stage                                                         stage                                                              tional            reaction                 reaction                      reaction                           reaction                                reaction                                     reaction                                          reaction                                               reaction                                                    reaction                                                         reaction                                                              reaction    __________________________________________________________________________

As can be seen from Table 1, each of the resins provided by the abovepreferred embodiments 1 to 10 gives a small value of Mw/Mn, which is ameasure of the breadth of the molecular weight distribution, whencompared to the resin provided by the comparison example 1, and thusoffers a narrow molecular weight distribution.

As can be seen from each of FIGS. 3 to 13, which show the results ofdetermination by gel permeation chromatography for the resins providedby the above preferred embodiments 1 to 10 and the comparison example 1,the molecular weight distributions for the preferred embodiments 1 to 10as shown in FIGS. 3 to 12 are narrow, compared to the molecular weightdistribution for the comparison example 1 as shown in FIG. 13.

With the present invention as described above in detail, novolak typephenolic resins can be provided which offer narrow molecular weightdistributions, and lower viscosity in molten state and, as a consequenceuniformity in curing time.

In addition, with this invention, the methods of manufacturing allow theabove stated novolak type phenolic resins to be provided by simpleprocesses at high yields.

What is claimed is:
 1. A method of manufacturing a novolak type phenolicresin, which comprises reacting an oxycarboxylic acid selected from thegroup consisting of tartaric acid, citric acid and a mixture thereof,with an aldehyde, and reacting the resultant reaction product with aphenol.
 2. The method as claimed in claim 1, wherein the novolak typephenolic resin has a ratio of (a)/(b) which is 0.05 or higher, where (a)is the number of units, with a carboxyl group, --COOH, and an alcoholichydroxyl group, --OH, in the oxycarboxylic acid being considered to formone unit, multiplied by the number of moles of the oxycarboxylic acid,and (b) is the number of aldehyde groups contained in one molecule ofthe aldehyde multiplied by the number of moles of the aldehyde.
 3. Themethod as claimed in claim 1, wherein the phenol is selected from thegroup consisting of phenol, cresol, xylenol, bisphenol A, bisphenol F,pyrocatechol, resorcinol, pyrogallol and a mixture of any two or more ofthese.
 4. The method as claimed in claim 1, wherein the aldehyde isselected from the group consisting of formaldehyde, paraformaldehyde,trioxane, tetraoxane, benzaldehyde, salicylaldehyde,p-hydroxybenzaldehyde, terephthalaldehyde and a mixture of any two ormore of these.
 5. The method as claimed in claim 1, wherein the novolaktype phenolic resin has a ratio of (a)/(b) which is 0.1 to 1.0 where (a)is the number of aldehyde groups contained in one molecule of thealdehyde multiplied by the number of moles of the aldehyde, and (b) isthe number of aromatic rings having a hydroxyl group contained in onemolecule of the phenol multiplied by the number of moles of the phenol.6. The method as claimed in claim 1, which is conducted in the absenceof any catalyst other than the oxycarboxylic acid.
 7. The method asclaimed in claim 1, wherein the novolak type phenolic resin has amolecular weight distribution, Mw/Mn, of 1.88 or less, determined by gelpermeation chromatography, where Mw is the weight-average molecularweight and Mn is the number-average molecular weight of the resin bypolystyrene conversion.
 8. The method as claimed in claim 1, wherein thenovolak type phenolic resin has a ratio of (a)/(b) which is 0.1 to 0.8where (a) is the number of aldehyde groups contained in one molecule ofthe aldehyde multiplied by the number of moles of the aldehyde, and (b)is the number of aromatic rings having a hydroxyl group contained in onemolecule of the phenol multiplied by the number of moles of the phenol.9. A method of manufacturing a novolak type phenolic resin, whichcomprises reacting an oxycarboxylic acid selected from the groupconsisting of tartaric acid, citric acid and a mixture thereof, with analdehyde, reacting the resultant reaction product with a phenol, andafter completion of the reaction, washing the resultant reaction mixturewith water to remove catalyst and dehydrating and concentrating theresultant mixture.
 10. The method as claimed in claim 9, wherein thenovolak type phenolic resin has a ratio of (a)/(b) which is 0.05 orhigher, where (a) is the number of units, with a carboxyl group, --COOH,and an alcoholic hydroxyl group, --OH, in the oxycarboxylic acid beingconsidered to form one unit, multiplied by the number of moles of theoxycarboxylic acid, and (b) is the number of aldehyde groups containedin one molecule of the aldehyde multiplied by the number of moles of thealdehyde.
 11. The method as claimed in claim 9, wherein the phenol isselected from the group consisting of phenol, cresol, xylenol, bisphenolA, bisphenol F, pyrocatechol, resorcinol, pyrogallol and a mixture ofany two or more of these.
 12. The method as claimed in claim 9, whereinthe aldehyde is selected from the group consisting of formaldehyde,paraformaldehyde, trioxane, tetraoxane, benzaldehyde, salicylaldehyde,p-hydroxybenzaldehyde, terephthalaldehyde and a mixture of any two ormore of these.
 13. The method as claimed in claim 9, wherein the novolaktype phenolic resin has a ratio of (a)/(b) which is 0.1 to 1.0 where (a)is the number of aldehyde groups contained in one molecule of thealdehyde multiplied by the number of moles of the aldehyde, and (b) isthe number of aromatic rings having a hydroxyl group contained in onemolecule of the phenol multiplied by the number of moles of the phenol.14. The method as claimed in claim 9, which is conducted in the absenceof any catalyst other than the oxycarboxylic acid.
 15. The method asclaimed in claim 9, wherein the novolak type phenolic resin has amolecular weight distribution, Mw/Mn, of 1.88 or less, determined by gelpermeation chromatography, where Mw is the weight-average molecularweight and Mn is the number-average molecular weight of the resin bypolystyrene conversion.
 16. The method as claimed in claim 9, whereinthe novolak type phenolic resin has a ratio of (a)/(b) which is 0.1 to0.8 where (a) is the number of aldehyde groups contained in one moleculeof the aldehyde multiplied by the number of moles of the aldehyde, and(b) is the number of aromatic rings having a hydroxyl group contained inone molecule of the phenol multiplied by the number of moles of thephenol.